NBCUniversal (NSDQ: CMCSA) will once again use its Olympics coverage to search for what it calls the “holy grail” of audience measurement. The media conglomerate has commissioned Google (NSDQ: GOOG) and research company comScore (NSDQ: SCOR) to develop new ways to measure viewership across broadcast, cable, internet and mobile platforms.

The 2012 London Games, which run for two weeks starting July 27, will be the third consecutive Olympics in which NBCU will conduct this kind of research. With the company offering its coverage across many platforms over a finite period of time, the Games typically provide an optimal test subject to conduct research on new metrics, NBCU officials say.

This time, however, the company is approaching the development of a so-called “single-source” metric with a little more urgency. Powerful voices within the TV industry are calling for an overhaul of the current ratings system, which lacks tools to measure audiences across platforms.

At the Consumer Electronics Show last month, Warner Bros. (NYSE: TWX) TV Group president and TV Academy chairman Bruce Rosenblum struck an industry chord when he equated the current ratings system to living in the “dark ages” and said it was “embarrassing” to the business. Having conducted experiments for the 2008 Beijing and 2010 Vancouver Games with tiny panels of 60 viewers or less, NBCU’s research this time around will feature much bigger audience samples.

Google plans to create a panel of about 3,000 consumers, using a meter-based system to track viewership across platforms. Google will also create algorithms specifically designed to measure this usage.

ComScore, meanwhile, will cull 750 Olympics enthusiasts from the 10,000-member audience panel it developed with AT&T (NYSE: T) AdWorks. Viewership data from this group will be compiled from a combination of AT&T U-verse set-top boxes, electronic meters and the self-reporting by panelist.

NBCU will not aim to create a true national sample with this research, but rather a proof of concept that shows the broadcast and advertising industries that such single-source metrics can indeed be created. “Cross-platform measurement is extraordinarily challenging, but we believe the unique and complimentary nature of these research projects will bring us one step closer to cracking the code of single-source measurement,” NBCUniversal research president Alan Wurtzel said in a statement.

NBCU has coined its research the “Olympics Billion Dollar Lab,” a reference to the $2.2 billion its shelling out to license London Games coverage across its broadcast, cable, Internet and mobile platforms. It has not announced programming plans across its various platforms yet. But it has confirmed that it will offer more than the 835 hours of coverage it offered for the 2010 Vancouver Olympics.